Process and apparatus for the combined pneumatic preliminary drying and pneumatic subsequent heating of goods



Sept. 19, 1933. osm 1,927,596

. PROCESS AND APPARATUS FOR THE COMBINED PNEUMATIC PRELIMINARY DRYING AND PNEUMATIC SUBSEQUENI' HEATING OF. GOODS Filed March 5, 1930 T y; n :5; 4

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Patented Sept. 19, 1933 PATENT OFFICE PROCESS AND APPARATUS FOR THE COM- BINED PNEUMATIC PRELIMINARY DRY- ING AND PNEUMATIC SUBSEQUENT HEAT- ING OF GOODS Paul Rosin, Dresden, Germany Application March 5, 1930, Serial No. 433,346, and in Germany March 9, 1929 3 Claims. (01. 34-24) It is already well known that pneumatic drying apparatus have a considerably greater efficiency than the ordinary drying apparatus. Where, however, there is a demand for a definite 5 heating of the material that is to be dried, beyond the actual drying of the same, the main advantages of the pneumatic drying apparatus, namely, a smaller capital outlay with greater efficiency and a more satisfactory consumption of heat, are to a greater or less extent lost. The satisfactory utilization of the heat of a single working pneumatic drying apparatus is based on the fact that the extent of the waste-heat losses is determined essentially by the dew point of the waste gases. Since in the case of every pneumatic drying process the exchangeof heat can take place in the continuous current, it will be found that where the drying process is followed by a heating treatment at temperatures higher than the final temperature of the drying process, the waste-heat losses in the case of a single working pneumatic drying apparatus are determined mainly by the ultimate temperature of the subsequently heated material; thus, the higher the ultimate temperature of the material, the less economically will an apparatus of this kind work.

By means of the process hereinafter described it becomes possible, even though the material to be dried may have to be subsequently heated, to

obtain, with a very cheap and eflicient apparatus-such as claimed for example-a very satisfactory consumption of heat from the single pneumatic drying part of the apparatus.

The present invention consists essentially in' the combination of a pneumatic drying apparatus and a pneumatic heater (a device for the exchange of heat), wherein these are so combined as to cause the hot gases to give of! a portion of their heat content first of all to the ma- 40 terial that has already been dried-for the pur-,

pose of subsequent heating-and then to give ofl the remainder of their heat content to the fresh material-for. the purpose of preliminary drying. By this means it becomes possible to heat the material and to submit to it a subsequent heating with the same hot gas in one and the same current, whereby, as is the case with the ordinary pneumatic drying apparatus, the waste-heat losses are determinable mainly by the dew point temperaturev of the hot gas after the drying process has been carried through. The process is suitable for any and all kinds of material which can be treated pneumatically.

An apparatus which works in accordance with the above escribed combined pro ess is shown diagrammatically in elevation on the appended drawing to which reference will now be made. The burnt gas passes at the necessary temperature out of the fiue a into the system of pipes comprising the pipes b, c, and d and thence 69 through the cyclone fan e into the piping f-g. The gas is sucked out of the pipe g either directly by means of the exhauster m or through a separating device h into the cyclone fan Z. The separating device it is included in the gascirculatory 5 system comprising the pipe g, the said device,

a pipe 1' and a disintegrator k which is connected to the pipe y. The material to be dried is fed through a suitable device 12. (for example, a screw conveyer) through the lock 0 into the pipe I. 70 From here it is carried along by the gas current I which separates it in the cyclone fan I. The lock 12 allows the pre-heated material to be fed through the pipe q into the hot gas current, which, after further heating the material, or if need be after the subsequent drying of the material, deposits. it in the pipe system b-d leading to the cyclone fan e. The finished material is discharged through the lock 1' and taken away by means of a suitable attached conveyer device s, or other means.

The heating system bd is shown in the drawing as a system of pipes telescoped one into the other. Instead of this, however, pipes lying alongside one another and connected by means 86 of quarter bends can also be used. The dimensions of the pipes and of the entire apparatus will naturally depend entirely upon the object and efficiency desired from time to time. Further, the rotary drying apparatus referred to in 90 the drawing can be replac d by a simple system of pipes. The pre-dried mate 'al may be, according to its condition and should occasion arise, carried away by means of some other conveyer device, instead of through the inclined pipe q. Finally, it may appear appropriate to place the devices 0 and q alternately in the falling and rising current of gas, or at some other point.

According to the desired temperatures of the material to be dried, the process can also be established in such a manner that the material to be treated passes through not only two, but

also several stages of heating; the quantitative proportions of the hot gas and of the material as also its characteristics can render these measures, inter alia, imperative.

Byway of an instance of the use to which the present process can be applied, the preliminary drying and preliminary heating of a slowly-burning coal may be men ioned. These procu esses are normally carried out in the first portion of the swealing oven, so that for theactual swealing itself it is only the remaining portion of the oven that can be used. But the propor- 5 tion of capital outlay necessary for the, drying and preliminary heating processes is in the case of a swealing oven considerably higher than the capital outlay in the case of a plant in accordance with the above described process. As against this, the somewhat greater consumption of heat, which is very much more satisfactory than in other drying processes, is negligible. Thus, the efliciency of an expensive swealing oven can be increased by the separate drying and pre-heating of the coal in a cheap and intensively working apparatus, such as is provided for by the present process, without any considerable consumption of heat.

I claim:

1. Apparatus for drying and subsequently heating materials, comprising in combination means for supplying hot gases, a system of pipes leading therefrom, a cyclone fan connected to said system, a separating device, a pipe con,- necting said cyclone fan to said separating device, means for feeding said. material into said pipe, adisintegrating device, having an inlet which is connected to said separating device and an outlet which is connected to said pipe connecting said cyclone fan to said separating device, a further cyclone fan, means for connecting the latter to saidseparating device, an exhauster device connected to said further cyclone fan, and means for connecting the further cyclone fan to said system orpipes at a point in closer proximity to said means for supplying hot gases than said pipe interconnecting said first mentioned cyclone fan to said separating de- VlOe.

2. Apparatus for drying and subsequently heating materials as claimed in claim 1, wherein said system of pipes comprises a number of telescopically arranged pipes arranged in contra-flow formation.

3. Apparatus for drying and subsequently heating materials as claimed in claim 1, wherein said system of pipes comprises a centrally arranged riser tube connected to said means for supplying hot gases, and wherein the bottom part oi said further cyclone fan is connected to said riser tube inclose proximity to the part of the latter connected to said means for supplying hot gases.

PAil'L ROSIN. 

